Data is not corrected after reordering if there are groupRowsBy?

I created a table with groupRowsBy and can reorder rows, but the result does not change after dragging and dropping the rows. Please help me with this case.

 this.data = [
  {
    id: 1,
    groupOrder: 1,
    group_by: { name: 'Manager', id: 1 },
    name: 'Manager 1',
    title: '1.1 Manager 1',
  },
  {
    id: 2,
    code: 1.2,
    groupOrder: 1,
    group_by: { name: 'Manager', id: 1 },
    name: 'Manager 2 ',
    title: '1.2 Manager 2',
  },
  {
    id: 7,
    groupOrder: 2,
    group_by: { name: 'Support', id: 2 },
    name: 'Support',
    title: '2.1 Support',
  },
];

Row Group Subheader enter link description here

Reorder enter link description here

This my code enter link description here

I am guessing the problem you are facing is that on drag and drop the datasource (this.data) is not updated. We need to do this programatically using the table row re-order event.

When you drag and drop, instead of listening to the drag event, you can listen for the prime-ng table event onRowReorder.

<div class="card">
  <!-- remove groupRowsBy="group_by.id" will corrcet data afert drop ??? -->
  <p-table
    [value]="data"
    sortMode="single"
    [scrollable]="true"
    rowGroupMode="subheader"
    groupRowsBy="group_by.id"
    (onRowReorder)="onRowReorder($event)"
  >
  ...

This provides you two details dragIndex and dropIndex .We can use these two details and swap the array elements, I have used the move element to another position in array answer below:

Move an array element from one array position to another

onRowReorder(data: any) {
  console.log(data);
  array_move(this.data, data.dragIndex, data.dropIndex);
}

Full Code:

TS:

import { Component, OnInit } from '@angular/core';
import { ImportsModule } from './imports';
import { CommonModule } from '@angular/common';

function array_move(arr, old_index, new_index) {
  if (new_index >= arr.length) {
    var k = new_index - arr.length + 1;
    while (k--) {
      arr.push(undefined);
    }
  }
  arr.splice(new_index, 0, arr.splice(old_index, 1)[0]);
  return arr; // for testing
}

@Component({
  selector: 'table-subheader-grouping-demo',
  templateUrl: 'table-subheader-grouping-demo.html',
  standalone: true,
  imports: [ImportsModule, CommonModule],
})
export class TableSubheaderGroupingDemo implements OnInit {
  data: any[] = [];

  constructor() {}

  ngOnInit() {
    this.data = [
      {
        id: 1,
        groupOrder: 1,
        group_by: { name: 'Manager', id: 1 },
        name: 'Manager 1',
        title: '1.1 Manager 1',
      },
      {
        id: 2,
        code: 1.2,
        groupOrder: 1,
        group_by: { name: 'Manager', id: 1 },
        name: 'Manager 2 ',
        title: '1.2 Manager 2',
      },
      {
        id: 7,
        groupOrder: 2,
        group_by: { name: 'Support', id: 2 },
        name: 'Support',
        title: '2.1 Support',
      },
    ];
  }

  rowTrackBy(_, item: any) {
    return item.id;
  }

  onRowReorder(data: any) {
    array_move(this.data, data.dragIndex, data.dropIndex);
  }
}

HTML:

<div class="card">
  <!-- remove groupRowsBy="group_by.id" will corrcet data afert drop ??? -->
  <p-table
    [value]="data"
    sortMode="single"
    [scrollable]="true"
    rowGroupMode="subheader"
    groupRowsBy="group_by.id"
    (onRowReorder)="onRowReorder($event)"
  >
    <ng-template pTemplate="header">
      <tr>
        <th>#</th>
        <th>item</th>
      </tr>
    </ng-template>

    <ng-template pTemplate="groupheader" let-item>
      <tr pRowGroupHeader>
        <td colspan="100" class="font-weight-bold">{{ item.group_by.name }}</td>
      </tr>
    </ng-template>

    <ng-template pTemplate="body" let-item let-rowIndex="rowIndex">
      <tr pDraggable="item" [pReorderableRow]="rowIndex">
        <td>
          <span class="pi pi-bars" pReorderableRowHandle></span>
        </td>
        <td>{{ item.code }} {{ item.name }}</td>
      </tr>
    </ng-template>
  </p-table>
</div>
<pre>{{data | json}}</pre>

Stackblitz Demo